Photographic synchronizer testing equipment



y 1944- J. A. SPRAGUE 2,353,896

PHOTOGRAPHIC SYNCHRONIZER TESTING EQUIPMENT Filed Sept. 30, 1942 7 Sheets-Sheet 1 K 2; MAL

/ -azzomg y 1944- V J. A. SPRAGUE 2,353,896

PHOTOGRAPHIC SYNCHRONIZER TESTING EQUIPMENT Filed Sept. 30, 1942 '7 Sheets-Sheet 2 IF 3 a R 86 -37 r ms July 18, 1944.

INVENTOR. rilfiprqyae 7 Sheets-Sheet 5 J. SPRAGUE PHOTOGRAPHIC SYNCHRONIZER TESTING EQUIPMENT Flled Sept 30, 1942 7 Sheets-Sheet 4 WT a a M 8 A; Mm i g Z July 18, 1944. J. A. SPRAGUE PBOTOGRAPHIC SYNCHRONIZER TESTING EQUIPMENT Filed Sept. 30, 1942 July 18, 1944. J. A. SPRAGUE PHOTOGRAPHIC SYNCHRONIZER TESTING EQUIPMENT Filed Sept. 30, 1942 7 Sheets-Sheet '7 1N VENT OR.

I Ma Q44 Patented July 18, 1944 UNITED STATES PAT'ENT: OFFICE PHOTOGRAPHIC SYNCHRONIZER TESTING EQUIPMENT Joseph A. Sprague, Honeo to The Folmer Grafl N. Y., a corporation 12 Claims.

tester in condition for making a record test, with the horizontal member in transverse section, showing the shutter and lens board with the electromagnetic tripper attached thereto, the sensitized material holder or carrier being shown in dotted lines Fig. 3 is a. rear elevation of Fig. 1, showing the position of the sensitized material holder or carrier prior to making a record test, the mechanism being in condition for making the same;

Fig. 4 is a vertical section through Fig. 3 on the line l-J thereof; I

Fig. 5 is a view similar to Fig. 2, but on an enlarged scale, showing the sensitized material holder or carrier in dotted lines in position for shutter operation;

Fig. 6 is a partial horizontal section through Fig. 5 on the line 6-8 thereof, showing the parts of the sensitized material holder or carrier when a record test is being made;

Fig. 7 is a fragmentary front elevation of the light valve or gate used when selecting the type of test to be made, i. e. a visual test or a record test, the light valve being in position for making a record test; I

Fig. 8 is a fragmentary view of a developed photographic sheet or chart showing both the trace produced by the photoiiash lamp and the trace produced through the shutter;

Fig. 9 is a top plan view of the synchronizer testing equipment when folded for storage or transportation Fig. 10 is a fragmentary, rear view detail of the sensitizedmaterial holder or carrier, showing the several openings used in checking the shutter by the visual test;

ye Falls, N. Y., assignor ex Corporation, Rochester, of Delaware Applicationseptember 30, 1942, Serial No. 460,313

Fig. 11 is a fragmentary view of one of the dark slides used when making visual tests, and

showing the position of the filters thereon;

Fig. 12 is a section through Fig. 9 on the line i2 I2 thereof, showing the position of the parts when folded for transportation;

Fig. 13 is a view similar to Fig. 1, with the testing device in condition for making a visual test;

Fig. 14 is a fragmenta nizer tester vertical fra for supporting the lens valve being set in c test;

Fig. 15 is a view similar to Fig. 2 but showing the sensitized materi al holder or carrier in dotted lines, in position for making a visual test; Fig. 16 is a view similar to Fig. 3, but showing the flash lamp in the position wherein the synchronizing testing equipment is in condition for making a visual test;

Fig. 17 is a view simll ing the mechanism visual test, the shutt tion so as more cle thereof; and

Fig. 18 is a sectio the position of the are in position for When a flash gu installed on a ca some means for c the peak of the photographic shu ry view of the synchrome, showing the means board, the gate or light ondition for making a visual ar to Fig. 5, but showin condition for making a er being in the open condiarly to show the structure n through Fig. 15, showing dark slide when the parts making a visual test.

n or photoflash equipment is mera, it is necessary to have necking the synchronization of flash with the opening of the tter. It is also necessary to have ries, very elabor ments, but ther equipment that the field and ate means for checking such equipc has long been need for a simple could be used in a dark room in that would give a quick visual check upon the performance of the apparatus, and if necessary make a photographic record of nce of the camera shutter when equipped with a flash synchronizing mechanism. My invention provides an equipment that does both things in a highly satisfactory manner.

Among the objects of my invention are: to provide a synchronizer for checking the performance of visual means with suflicient accuracy so that the operator will have full confidence that his synchronizing equipment and shutter will be fully synchronized; to provide a synchronizing equipment that will produce a photographic record of the performance of the synchronizing equipment and synchronization of the shutter wherewith it operates; to provide a synchronizing a synchronizer equipment by a equipment that is simple and foolproof in operation and that can be readily operated by any one having suflicient knowledge to operate a photographic camera; to provide means for quickly attaching and holding in proper spaced relation a photographic shutter and a lens equipment mounted on a lens board; to provide a .simple sensitized material holder that can be loaded with a sheet of sensitized material for providing a permanent photographic record; to provide a synchronizer testing equipment that can be folded into a small package for transportation; and to provide simple means for furnishing illumination when testing ynchronization by the visual means.

Referring first to Figs. 1, 2 and 3, the structure constituting the disclosed embodiment of my invention is mounted on a table 20 or other suitable support, upon which is positioned in a faceto-face relation therewith (being secured thereto if desired) a base supporting member 2|, preferably of wood, shown as rectangular in cross section, and to which is attached a vertical support member 22 preferably of sheet metal and attached to the said base supporting member 2| by screws 23, shown in Figs. 3, 4 and 16. Fitted into a hole 24 of said member 2|, as shown in Fig. 9, is a flash synchronizer battery case indicated as a whole at 25. The hole 24 is of such shape or diameter as adapts it to receive battery cases of usual diameter, or means may be provided to receive and support upon said member 2| battery cases of different diameters. If desired clamping means may be substituted for the hole 24 to hold the selected flash battery case in position.

As indicating the use of the disclosed embodiment of my invention, I have shown as an example of a synchronizer that may be tested in the testing equipment, the synchronizer that is disclosed in the patent to Oscar Steiner, No. 2,329,011, dated September 7, 1943, but it is to be understood that my invention is in no wise limited in its use to the testing of the type of synchronizer shown in said Steiner patent, as my testing equipment is intended for use in testing synchronizers differing widely in construction.

The illustrated battery case 25 is provided with an appropriate reflector 26 and a iiashlamp is indicated in dotted lines at 21.

A lens board receiver 22 is attached to the vertical support member 22 by screws 29, being most clearly shown in Fig. 5. As there indicated, and also in Figs. 2, 3, etc., it has fitted thereinto a lens board 32 wh'ereon is mounted a shutter 2| having a lens 32, such lens board 20 being held in position by retaining springs 32, pivoted to the vertical support member 22 by screws 24. Also mounted upon the said vertical support member 22 is an electrical switch 35 held in position by an insulating strip 22 to which the switch ll is secured by screws 21, 21, the said insulating strip 36 being itself held to the vertical support member 22 by screws 12, shown in Figs. 3, l2 and 16. The said switch I! is provided with the usual contact screws 29, to which are attached a pair of bus-bars l0, terminating under the heads of screws 21, which pass through the body of the switch 35 and serve as contacts to which embodiment of my invention, the series outlet to which the connecting plug 44 is applied has been uncovered by swinging downward the battery case switch I! out of functioning position, as shown in Fig. i. In making a test the switch II is substituted in function for the switch ll in the manner described.

Also shown as attached for testing purposes to the battery case 25 is a second electrical connecting plug it fitted into any one of the parallel outlets of the battery case 25, said plug 40 being attached to a cable 41 consisting of the wires 42, 40. The opposite end of the cable 41 is provided with an electrical plug 50 fitted into a to-and-fro or axially movable element ll of an electromagnetic tripper 52 held to'the lens board II by a tripper bracket 82 itself attached to said lens board by screws 54, 5|.

Referring particularly to Figs. 2 and 3 and also to Figs. 1 and 6, the said electrom snetic tripper I2 is in mechanical connection with a shutter release arm by means of a connecting link I. or in any other suitable or desired manner. The shutter II is provided with the usual set lever 51. The vertical support member 22 is desirably of a channel formation as shown most clearly in Fig. 6, and it is of a shape and construction to receive a sensitized material holder or carrier ll, shown in dotted lines in Figs. 1 and 2 and in solid lines in Fig. 3, which contains sensitised material a. Hereinafter the part II is referred to as the holder, merely for convenience of description.

The structure and proportions of the channel formation of the vertical support member 22 with respect to the sensitized material holder I are such that the said holder 52 will drop freely in a vertical direction when released by the means now to be described, constituting a part of the testing equipment. In order to maintain the said holder 62 in its initial position before the dropping thereof, I provide any suitable means, but for the purpose I have herein represented latching means consisting of a lever ll having a release pad I for manual manipulation, said lever being secured to the vertical support membe 22 in a horizontal position on a bracket ll, ll, itself held to the vertical support member 22 by means of screws 82, 02 (Fig. 2). The said lever II is itself attached to th bracket ll by a shoulder screw 03, being free to pivot thereon, and is provided with a laterally extending finger 24, best shown in Figs. 1, 9 and 13. The purpose of the said finger N is to engage a ledge 82 of the sensitized material holder II, best shown in Fig. 3. which is formed by Providing an opening in the said holder 2!. The vertical support member 22 is provided with a suitable opening it through which passes the said laterally extending finger I, as best shown in Fig. 9.

When the sensitized material holder II is engaged by the said laterally extending finger N. the said holder is held in the position indicated in Figs. 1, 2 and 3. When, however, the pad ll of the lever 58 is pressed by the operator in a rearward direction so as to withdraw the finger ll from the ledge ll of the holder II, the latter is permitted to drop vertically.

The switch 2!, best shown in Figs. 1, 5, and 13. is provided with an operating arm ll. The said switch is desirably a standard switch obtained on the open market and is preferably of the type known as Microswitch and the operating arm l'l is a part of the said switch as purchased.

The vertical support member 22 is provided with a suitable cut-out or opening OI, as indicated in Figs. 1 and 12, to allow the arm 01 to extend through one of the side walls of the ver- I assassc tical support member 22, so that the switch operating arm 61 extends into the path of the sensitized material holder 33 when the latter is permitted to drop in the vertical support member 22. This action is best indicated in Fig. 3, wherein the switch operating arm 31 is shown depressed as the sensitized material holder 38 passes said operating arm. When the said sensitized holder 33 reaches the position shown in Fig. 5, the said switch operating arm 81 is moved by the said holder 53 in a left hand direction viewing said figure, thus operatin the switch" and closing the contacts thereof. This movement completes a circuit between the wires ll, 42 constituting the cable 43 and which, as already stated, is connected to the synchronizer battery case 25 by the plug 44, thus causing the lamp 21 to be ignited and the electromagnetic tripper 32 to be operated, thereby operating the camera shutter 3| Just as such shutter would have been operated had the switch 45 of Fig. 1 been operated in the usual manner in taking a photograph by the camera, instead of by operating the switch 33 of the testing equipment.

The sensitized material holder 33 is a standard film holder with, however, certain modifications to be presently described. For the purpose of making a record test by my equipment, no modiilcation of the film holder 33 from a standard construction is necessary.

The operation of the structure thus far described is as follows:

The sensitized material holder 33 is loaded with a sensitized sheet of paper or film and is placed in the channel of the vertical support member 22, being retained by the latch member or lever 33 until it is desired to make the test. When a test is to be made, the dark slide of the holder 33 having first been-withdrawn, the said holder is released by the latch member or lever 33 and drops by gravity, and upon reaching the switch operating arm 61 the switch 33 is operated, thereby completing the circuit through cable 41 to battery case 25, flashlamp 21 and electromagnetic tripper 32, thus operating the shutter 3|.

In order to ascertain the instant of time when the shutter 3| is caused to open with relation to the flash of the photoflash lamp 21, I have provided two openings 33, 10, in the vertical support member 22, as shown in Figs. 2, 3, 5, etc. The opening 63 is of smaller diameter than the opening so as to allow a reduced amount of light to pass therethrough, thereby providing an opportunity better to record the light intensity, since, as is well known, the more light passing through the holes 39, 13, the denser will be the exposure. The perforated area provided by the openings 89, 10 admits lights from the flashlamp to the sensitized material, such perforated area being shaped to admit such light in varying intensity at different parts thereof, merged as shown.

As the sensitized material holder 33 passes the switch operating arm 61, as previously described, and thus causes the flashlamp 21 to be ignited and the shutter 3| to be operated, the sensitized material 580, that is in the said holder 33 will be behind the holes 69, 10, and said holes 39, 10 and the shutter opening of the shutter 3| all receive light from the flashlamp 21. Therefore an unexposed area of the sensitized material 53a will appear behind the opening 1|, provided in the front face oi? the vertical support member 22, as shown in Fig. 3, and which opening 1|, as there shown, is aligned with the center of I of the shutter.

the opening of the shutter 3|, as indicated in Fig. 5, an unexposed area being also behind the holes 63, 13, previously referred to. That is, said opening 1| is in what may be termed line-ofvision register with the center of the opening Therefore, light is admitted to the sensitized material 33a in the holder 33. Inasmuch as the holes 39, 10 are always open, the sensitized material 33a will be exposed during all of the flash of thephotoflash lamp 21, but light is excluded from the hole 1| by the shutter 3| at all times excepting when the shutter aperture is open, it being noted that the shutter aperture is controlled by the electromagnetic tripper 32, as previously explained. With respect to the making of recorded tests, opening 1| is used and also either opening 83 or 10 or both 33 and 10. In

practice, I have found that itis better to use two openings 33 and 13, one larger than the other, thus giving the appearance indicated at the left in Fig. 8 at 13, to be more fully referred to, but it is not essential to my invention that both openings 33 and 13 be employed.

Therefore if a photoflash lamp is placed in the socket of the battery case 23 and the holder 33 of suitable construction is loaded with sensitized material 33a, and is placed in the vertical support member 22 and then allowed to drop by manual manipulation of the latch member or lever 39, a circuit is completed to the flashlamp 21 and the electromagnetic tripper 52, as already explained. Consequently a flash will take place and will be recorded for the full length of such flash through the holes 39 and 10, and during the time that the shutter is open, light will pass through the hole 1| to the sensitized material 58a and will also be recorded.

Upon development of the sensitized material 380, the exposed areas will appear as clearly indicated in the chart Fig. 8, wherein the area behind the shutter opening 1| will appear as indicated at 12, and the exposed area behind the openings 39 and 10 will appear as indicated at 13. When the exposures do appear as in the chart Fig. 8, the shutter is in proper synchronous relation (that is, it is simultaneous in functioning with the flashlamp as indicated at the exposed area 13).

It will be noted that the exposed area indicated at 13 in the chart Fig. 8 builds up from no exposure to a very dense exposure, and then drops down to no exposure. It is desirable to have the opening of the shutter 3| take place during that area of greatest illumination, that is, to have it occur between the dotted lines a and b of the chart Fig. 8. If, however, the exposed area 12 appears below the dotted line a or above the dotted line b of the chart Fig. 8, the shutter 3| would be out of synchronous relation with the fiashlamp (i. e., would not be functioning simultaneously therewith). If the said exposed area 12 appeared below the line a, the shutter 3| would be operated too soon. If said exposed area 12 appeared above the line b of the chart -Fig. 8, the shutter 3| will be operated too late. The lines a and b of the chart Fig. 8 therefore represent the desirable area in which the shutter 3| should be operated. In the instance illustrated in the chart Fig. 8, the shutter 3| was operated within the said desirable area but slightly early in time, being nearer the dotted line a. This is the preferred adjustment because with use the battery of the synchronizer will become deteriorated and the synchronizer will consequently operate slightly more slowly. Therefore, as the battery voltage drops the exposed area 12 would move slightly upward with respect to the chart Fig. 8 if a further test were to be made.

The speed at which the sensitized material holder 58 travels downward when released is not critical, but the position along the vertical support member 22 of the switch 35 with its operating arm 61 should be such that the fiashlamp 21 will be ignited during the time that the sensitized material 58a in the holder 58 is in position behind the holes E9, 10 and ii. After such position for the location of the switch 35 along the support member 22 has once been located either by mathematical determination or by experiment, no further adjustment of parts is required for making a record test by the testing equipment herein disclosed. Since the entire duration 01 the flash is recorded, and since the holes 68, 10 in the support member 22 are in horizontal alignment with the hole 1i, it is always an easy matter to plot the exposed area 12 against the exposed area I3, and since the entire length or the exposed area I3 never is greater than twenty-five per cent or the length of the piece of sensitized material "a, a. considerable latitude is allowable in the adjustment of the position of the switch 36. Nevertheless for best all round performance I have found that the proportions represented in the drawings of this application are the correct proportions oi the vertical support member 22 with th illustrated position of the switch 35 being ideal for the testing of all fiashl'lmps of known manufacture.

The sensitized material holder 68 is of the usual construction but with slight modifications when used for visual tests. The structure of said holder 58 is most clearly evident from Fig. 6, wherein it is represented as provided with separating plates ll, 15, film retaining strips I6, I6, grooves 11, H for receiving dark slides, and the dark slides ll, 18, only one of which is shown, the other having been removed to make exposure of sensitized material 51a in the manner previously described.

When the testing equipment of my invention is used for making the visual test, the holder BI is not loaded with sensitized material, but its position is reversed as it is placed in the vertical support member 22, so that an opening I! or the dark slide 18 of the holder (shown in Fig. 6) is in alignment with the hole ll of the vertical support member 22, is dropped, said opening 18 comes in line-oivision register with the hole ll of the vertical support member 22) and the openings M, II or the separating plates 16, M respectively (shown in Fig. 6) are in horizontal alignment with an opening 19 in dark slide 18, and are of sufllcient length to uncover holes 82 and 62, also provided in the dark slide 18. This structure is best shown in the sectional view Fig. 18. The said dark slide 18 is provided with the said three openings 19, 82, 83. The opening 82 is provided with a red filter, indicated at H, and the opening 82 is provided with a green filter, as indicated at 85. My invention is not limited to the provision of filters of the stated colors, as any two suitably contrasting colors may be employed.

When the dark slide I8 is in position for making a visual test, the holder parts will appear as shown in Fig. 18, and when they are in position for making a record test, the holder parts will be positioned as shown in Fig. 6.

For making a visual test, two additional holes are provided in the vertical support member 22, being indicated in Fig. '7 by dotted lines at 68, 81, and in full lines in Fig. 14, and in section in Fig.

(that is, when the holder 56 18. The three holes ll,

Figs. 3 7 14 and 16 as i n a true vertl which is their preferred relation, but tfi wh i h etxezct relation my invention is obviously not limtogth'l'hg must be in any case near enough 0 er be within the confines or the shutter t.hpening when the shutter is opened fully and ticeilmloitriigarlybthey are arranged in a. true vern, o v ously the greater will be ti.me required for the sensitized-material hold dto pass all of said holes. When making a rec- 25v tat, it is necessary that the holes I6, ll are was; or capped. For this purpose, I have proshoemanlilglht vealve consisting of a disk 08 best gs. and 14 as mounted zitagtiupggttmember 22, and as havin g a 1 12:13;

ac hereto by rivets Th valve or disk 88 is provided I 8 said light th openin ii 62 for alignment with th W1 88 and e openings I! respectively. When the said light valve i di k be s position for making a visual test it will ligh zrecilsely as indicated in Fig. 14 The said va ve or disk as is held 1 1 ll concentric therewith n p ace by a ring and secured to th :ical fillpport member 22 by large headed S CI e rand e said concentrically arranged ring 92 is gimme; 21:33; itilxlmge 96 having an opening into e said light valve or disk girl; stckrews N, and washers a are provided ring uealrilgdht valve or disk II in position in the bet against the vertical support mem- When the said light valv e or disk ll inleahilggllrwias: tdirection viewing Figs. 7 92: e revels in a slot pro ided I in the ring 92 The 0 v therefor penings ll and 92 i be moved out of ali w 11 thus gnment with the 0 nl 831d thereby all light is prevented i i orri pass "I m: rough the holes ll, ll or from reaching lightsenzit igegrmgtirigls "a in the holder II. The

s is in this positi making a record test and wh on when its handle II is moved in a. contraclockwis Figs. 7 and 14 the ho] e rectum viewing e 9| of the light valve ((1312:; will be in alignment with the hole I will the,n11;!lilnle-tolf-vision register). The parts e position shown 1 lvh iizlsailstihs IXIJSIUOXI oi the parts wh n :12 111: s nasmuch as the o in II or the separatin Pen 88 a lad g plates 16, II will be in all gexngzvsithuthe hole H and the holes I6, 61, light B. and shmrlfgurglzhthe sriisitized material holder Y e ve cal support membe and the disk II when the said r n itized m teri holder ll reaches the sens a a1 position shown in F1 and also thro g- 18' ter is open ugh the shutter 8| when such shut- In order to provide a fixed source 01 illumina- 32:1! use when making a visual test, the vera support member 22 ha attached thereto 1supplemc-intal support member II by means or r lists 61, best shown in Figs. 9, 12 and 16 and :1 V1 in Figs. 1 and 3, said support member I! 9. ng a suitable rormation OI to which is hung as shown in Figs. 13 and 18 a fiashlamp 98 by means of a bail I00. The flashlamp II is of the structure best shown in Figs. 13 and 16 and is the standard flashlamp as carried by armed {orces oi the United States, said flashlamp functioning in the usual way. It is of the right angle ype and is so positioned that the holes ll .1 and H will be illuminated when the battery of said flashlamp 99 is in place and the switch 89; has been operated as indicated in Fig. 13.

n Fig. 13 the equipment is shown set up for I and H are shown in making a visual test. The synchronizer battery case 20 is laid on the horizontal member 2i and the cable 41 is plugged to the electromagnetic tripper 02 by means of plug and to the battery case by means of the plug ll. The switch is connected to the battery case 20 by means of the cable 43 and the plug 44. When the sensitized material holder 00 is released in the manner previously described, the shutter 3| will be operated as previously set forth.

In order to make a visual test, the light valve or disk 33 is set in the position shown in Fig. 14 and the sensitized material holder 53 is placed in the position shown In Fig. 15. When such holder 33 is placed in the vertical support member 22, in the position indicated in Figs. 15 and 16, and is allowed to drop by releasing the latch member or lever 03, the electromagnetic tripper 32 will be operated when the said holder II reaches the switch operating arm '01, by completing a circuit'through the cable 43 to the battery case 20 and to the electromagnetic tripper 32 through the cable 01, the flashlamp 00 having previously been illuminated manually in the usual manner. The shutter 3| will be caused'to open by the completion of the circuit as stated, and the operator will see the light from the flashlight projected through the openings 00, 01 if the shutter is in proper synchronous relation with the fiashlamp 21.

If light is visible only through holes 01 and II the synchronizer has been adjusted to function too early for the best results, and if light is seen only through holes II and II, the synchronizer has been adjusted to function too late for the best results. The synchronizer tripper should then be adjusted so that light will be visible through all three openings 01, II and 00.

The filters 34, II are provided in order that the operator may determine through what holes the light passes. When a start is made on adjusting the synchronizer by beginning the visible test now being described, it is very likely that the adjustment of the synchronizer will be found to be far from correct. Therefore, at the beginning of the test of the synchronizer, it is probable or possible that the operator may see light through one hole only, and if light that he sees is green, he will know that the position of the synchronlzer has been improperly set for too late functioning. If, on the contrary, the operator sees only a red light he will know that the positioning of the synchronizer is too early. If he sees a green light and a white light, he will know that the positioning of the synchronizer is close to the correct position, but is still too late, and if he sees a white light and a red light, he will know that the positioning of the synchronizer is early but very close. All that is necessary is for the operator to make adjustment in the proper direction so that he will see both a red light and a green light, and of course when he sees them, he will also see a white light. He will then know that the synchronizer being tested is in a position of correct adjustment for proper functioning.

When using the visual synchronizer test, itis important that the switch 38 be in proper position with respect to the sensitized material holder 58 when contact is made at the switch 35, so that there will be a proper time delay between the time of contact and that instant when the openings 83, 82 of the said sensitized material holder are in alignment with the openings l1, 00 of th vertical support member 22 (that is, in line-of-vision register). This can be readily checked when using the synchronizer test as a recording test. It is only necessary to adjust the synchronizer switch 33 and its operating arm 61 in a vertical direction so that the flash takes place at a proper instant of time with respect to the opening II. After this adjustment has once been made for a flash bulb of given manufacture (that is to say, for a flash bulb known to have a certain time delay, such, for example, as twenty milliseconds), all tests can be then made without further adjustments so long as flash lamps having that time delay are used with the synchronizer that is being tested.

The synchronizer testing equipment herein disclosed is flrst adjusted by making a record exposure and the position of the switch 30 is adjusted in a vertical direction along one sid of the vertical support member 22, so that the flash as indicated by the exposed area 12 is located between the dotted lines a and b of the chart Fig. 8. The position of the switch 30 with respect to the position of the sensitized material holder II at the time contact is made will then be correct for making a visual reading when testing lamps known to have the same time lag or delay. If it is desired to tests lamp having a known different time lag or delay, the switch 30 must be moved along and readjusted on the vertical support member 22 until the exposed area I2 will be between the lines a and b of the chart Fig. 8. If the flashlamp is being tested that is of a different characteristic than the one illustrated in the chart Fig. 8, bywhich is meant a flashlamp having a longer duration of flash or a shorter duration of flash, the space between the dotted lines a and 17 must be increased or decreased accordingly, and of course it will be necessary to adjust the position of the switch 30, so that the flash, as indicated by the exposed area, I2 will be between the repositioned two lines a and b. Since the holes 09, I0 and II on the vertical support member 22, through which light passes, are in horizontal alignment when the shutter tripper is once adjusted for making a record test, the exposed areas I2 and I3 will always be as indicated in the chart Fig. 8.

The synchronizer testing equipment herein disclosed is desirably of such construction that it can readily be folded for transportation or storage. To that end the base member 2I is provided with two elongated slots IN and I02 along the opposite lateral edges thereof, as indicated in Fig. 2. The said vertical support member 22 may be detached from the base member 2| by loosening screws 23, and the vertical member 22 having the turned-over end or U-shiped formations I03, I03, shown in Fig. 12, can be slid into the said parallel slots IOI, I02, after having been removed from the base member 2|, as most clearly shown in Figs. 9 and 12. Attached to the screws 23 are rubber bumpers I03 to absorb shock when the sensitized material holder 03 reaches the limit of its downward travel following its release by movement of the latching means or lever 59.

A rsurn of the operation of the disclosed synchronizer testing equipment is as follows.

. The equipment is assumed to be in that position of the parts shown in Fig. 9. The Vertical support member 22 is first withdrawn from the parallel slots IOI, I02 of the base member 2I and the screws 23 are loosened a suilicient distance to allow the notch openings I00 of the vertical support member 22 to be slid behind the heads of the screws 23, which are buried in the rubber bumpers I04 and washers I06, one of said washers being shown in Fig. l. The screws 23 are then tightened and the equipment is therefore in the position shown in Fig. l. A flashlamp battery case such as 25 is then mounted in the hole 24 or is held in position by clamping or other means as hereinbefore indicated. The lens board 30 having mounted thereon a shutter 3| and lens 32 is then placed in position in the lens board carrier 28 and is securely held thereto by means of the springs 33. The plug 46 of the cable 41 is then connected to the battery case 25 and the plug 44 of the cable 43 is also connected to the said battery case, as clearly shown in Fig. l.

The sensitized material holder II is loaded with a sheet of sensitized material "a, it being understood that the entire apparatus is in a photographic dark room in the field or other place of use. A flash lamp or bulb 21 is placed in the socket of the battery case 25, the shutter ll is set for the desired shutter speed, and the sensitized material holder 58 is allowed to drop by the releasing action of the lever 59 constituting the latching means. When the said sensitized material holder 58 reaches the contact spring 81, a circuit is completed between the wires 4| and 42, thus causin! the flash lamp 21 to be ignited and the electromagnetic tripper II to be operated in the manner previously described. The shutter 3| will then be caused to be opened and the sensitized material 58a will be in position behind the holes is, ll, II in the vertical support member 22, thus exposing the sensitized material 58a and upon development thereof it will appear as shown in the chart Fig. 8 if the tripper is properly adjusted.

If the exposed area 72 is below the line a of the chart Fig. 8, it will be necessary to adjust the electromagnetic tripper I2 so that the said shutter II will be operated relatively later than when the described test was made. If the exposed area is above the dotted line b of the chart Fig. 8, the electromagnetic tripper I! must be adjusted to cause the flash to occur relatively earlier than in the described test. When a proper adjustment has been found and the sensitized material "a is developed, the latter will appear as shown in the chart Fig, 8, where the exposed area 12 will be cated between the dotted lines a and b of the chart Fig. 8. v

In order to make a visual test, the sensitized material holder 58 is reversed in position, but is held from dropping by the latch member or lever 59, the flashlamp 9! is hooked onto the flashlamp support 98, and the switch "a is operated in usual manner to cause the flashlamp 98 to be illuminated. Said sensitized material holder ll is then released by pressing upon the pad 0 of the latch member or lever ll, whereupon said holder 58 drops. As the shutter ll is operated in the manner previously described, one or more of the holes 81, ii and N will be illuminated and the electromagnetic tripper U2 is adjusted to cause the said shutter to be operated either later or earlier depending on which holes are illuminated, until an adjustment is reached where all three holes 81, H and 88 are illuminated as described. The operator will then see a green light and a red light with a white light between them.

The battery case 25 is usually laid flatwise on the horizontal base member 21 when making a visual test rather than positioning it upright in the hole or other support provided therefor, so as thus to provide a clear path for the operator to view the holes 81, 1| and as through the lens 32.

The syuchronizer tester equipment herein disclosed can be used both for making recorded tests and visual tests. This is very desirable because at times the adjustment is made by someone other than the operator of the camera, and it is very desirable that the operator of the camera have at his disposal the record of the performance of his synchronizer equipment.

It is, however, necessary to use at least one flashlamp when making the record test. The visual test method is used for quick checking upon the performance of the synchronizer equipment, and it is also used when a record test is to be made. The usual procedure is to adjust the synchroniner as accurately as possible by the visual method and then to make a record test. In this way it is necessary to use only one flashlamp.

Actually. in the experimental work and in the designing and building and testing of the equipment herein disclosed, it was necessary to flash a great many lamps in order accurately to ascertain the correct position for the switch I5. After such correct position for the switch 3! has once been found, additional apparatus can be manufactured from fixed measurements, since the velocity of the sensitized material holder II remains constant enough for all practical purposes. Therefore, it is never necessary for the operator of the disclosed equipment to use more than one flash bulb in adjusting any one synchronizer, inasmuch as he first proceeds to make his adiustment by the visual method, and when all three holes (that is. the red, the white and the green holes) are seen when making the visual test, the record test which follows will be that shown in the chart Fig. 8, and it is only necessary to make the recorded test when the record of that test is to be used for furture reference.

I am aware that heretofore there has been provided an equipment having visual testing means for photoflash synchronizers, but so far as I am aware I am the first to provide a testing equipment for photographic flashlight synchronizers by which a visual test can be made and by which a record test can also be made.

So far as I am aware, I am the first to provide an equipment for testing synchronizers having electromagnetic trippers.

Heretofore no means has been provided so far as I am aware for checking a synchronizer tester. In other words, the operator has heretofore been compelled to assume that the testing mechanism is functioning properly. I have, on the contrary, provided means for readily checking the performance of the tester. By my invention I have provided a synchronizer tester particularly adapted to be used with electromagnetic tripper synchronizers, and I have provided means for visually checking the synchronization to a high degree of accuracy, and I have also provided means to obtain a record of the synchronization test. No one heretofore so far as I am aware has produced an equipment or device having such capacities.

The disclosed equipment, while very simple in construction and one which can be manufactured at relatively low cost. is the result of a great deal of experimentation covering a period of several years, and it has been found in practice that the results produce by the disclosed equipment are equal to the accuracy of the flashlamps that are being tested. The disclosed equipment is so simple that anyone capable of maki g a photograph can readily understand it oporation and can produce very accurate results regardless of the lack of previous experience,

and inasmuch as the entire equipment can be ioldedinto a compact package, th equipment 'can readily be transported 'for usein a dark.

room in the field and there set up for'operation in a very few minutes.

Having thus described one mentor the invention. it is to be understood that although specific terms are employecithey are used in a generic and descriptive sense and not (or purposes of limitation, the scope of the invention. being set iorth in the following claims.

I claim: l. A testing equipment for photographic flashlamp synchronizers of the electromagnetic shutter-release type, including in combination: .a vertical support and guide member provided with means for supporting a shutter and shuttertripping means; a iia'shlamp supported in front of 'said shutter, saidsup'ported shutter'being interposed betweensaid support and guide member and the flashlamp; a sensitized material holder slidable downwardly in said. member; a switch mounted on said support andguide member in said sensitized materiallholder the ilashlamp is ,operated and the shutter is momentarily opened; lsaid vertical support and guide member having a shielded'portion. provided with two horizontally aligned light-passage openings, one only of opening being exposed at all times to the light irom the flashlamp, and said sensitized material holder being located and adapted in a recorded test to be dropped behind said two openingsof said shielded portion, so aa'i'ndropping, to present' such sensitized-material for the recorded testand to actuate said switch, thereby to complete the circuit to the flashlamp and to cause said electromagnetic tripping means to open the supported shutter, and thus expose one of said two openings for the making of a record area on such sensitized material in the holder, and also simultaneously exposing the other of said two openings for the simultaneous making of another record area on the said sensitized material through said second opening, and spaced laterally from the first referred to record area, thereby to determine whether said two record areas are in svfiiciently close horizontal alignment to indicate substantially correct synchronization.

2. A testing equipment for photographic flashlamp synchronizers of the electromagnetic shutter-release type, including in combination: a vertical support and guide member provided with means for supporting a shutter and shutter-tripping means; a ilashlamp supported in front of said shutter, said supported shutter being interposed between said support and guide member and the flashlamp; a sensitized material holder slidable downwardly insaid member; a switch mounted on said support and guide member in the path of sliding movement of said holder, said switch being in electrical circuit with said shutter tripping means and with said fiashlamp and with a source of potential, so that when said switch is closed by the downward movement of said sensisized material holder the flashlamp is operated and the shutter is momentarily opened; said vertical support and guide member having a,

illustrative embodi- J said openings being behind the shutter, the other shielded portion provided with two horizontally aligned light-passage openings, one only of said openings being behind the shutter, the other opening being exposed atall times to the light from the flashlamp, said shielded portion being also provided w'ithtwo other light-passage openings respectively above and below one of said openings and sufiiciently close thereto so that the three openings are within the area ofthe opening of the supported shutter, and said sensitized material, holder being located and adapted in arecorded test 'to be dropped "behind said openings in said shielded portion, so as, in dropping, to actuate said switch, thereby to complete the circuit to said'flashlamp and to cause said electromagnetic tripping means toopen the jsup 'ported shuttenfland thus expose one o f ,s aid openings for the making of a record'iarea on the presented sensitized'material carried 'in the holder.

3. A'testing equipment forphotographic flashlamp synchronizers including, in cornbination, a sup t member having a shielding iacet'hat is upright when in operating position, alehsboard ,receivenattached to such shielding" face of said ,support member'and itseifl adapted to have attached temporarily thereto a'carnera lensboard and. shutter forgthe "testing operation, a tripper for the shutter, .an' elec'trical switch mounted on s p rt jn embe in "a osi n to b operated by' a dropped element, which i for recorded tests isaloadedsensitized niaterial holder presenting such material'ior the ftest, 'andwhich element isdropperj; inlltheftest from a point "above said switch, means for positioning in-suitable relation to said upright support membena synchronizer battery case Twith flashlamp "and source "of potential, circuitwiring means for connecting said battery case, fiashlamp, source of potential, and actuable movable element that is connected to the tripper of the shutter used in the testing'operation, the said support member with its said shielding face having a construction to receive and then to permit to drop therein behind said shielding face such element when released, so as by such dropping to operate said electrical switch, thereby to complete the circuit to the ilashlamp and to actuate said movable element connected to said shutter'tripper, the said shielding face being provided with two horizontally aligned light-pasi ge openings, the said shutter being supported in front of one only of said openings, the said x'iashlamp being supported in horizontal alignment with said openings in said shielding face, the other of said openings being expos'edat all times to the light from the flashlamp.

'4. A testing equipment for photographic flashlamp synchronizers including; in combination, a support member having a shielding face that is upright when in operating position, a lens board receiver attached to such" shielding'iace of said support member and itself adapted to have attached temporarily thereto acamera lens board and shutter for the testing operation, a tripper for the shutter, an electrical switch mounted upon said support member in a position to be operated by a dropped element, which, for recorded tests, is a loaded sensitized-material holder presenting such material for the test, and which element is dropped 1n the test from a point above I 'said switch, means for positioning in suitable relation shielding face such element when released, so as by such dropping to operate said-electrical switch, thereby to complete the circuit to the flashlamp and to actuate said movable element connected to said shutter tripper, the said support member being provided in the said shielding face thereof with two openings in .close proximity, one" being larger than the other, and 'behind'which two openings the said dropped element passes and both of which openings receive light from the said flashlamp and also admitlight to the sensitized material if carried in such dropped element, said two openings being in such close proximity that when the flashlamp is emitting light, the light through said two openings merges when striking the sensitized material, vsaid shielding face being also provided with another opening,

" ings in the shielding face as are used in making which is positioned 'in' lline-o'f-vision register with the center of the opening of such shutter,

said three openings providing for a recorded 'test and being ail'in'horizontal alignment.

5. A testing'equipment for photographic flashlamp synchronizers of the electromagnetic shutter-release type including, in combination, a vertical support and I guide member provided a with means'forsupporting a shutter and shutter tripping means, a flashlamp supported in front ofssid shutter, said supported shutter being interposed between said support and guide member and the jilashlamp, a dropable element slidable downwardly in said member, a switch mounted on said support and guide member in the path of sliding movement of said droppable element, said switch being in electrical circuit with said shutter tripping means and with said flashlamp and with the source of potential, so that when said switch is closed by the downward movement of said sensitized dropable element the flashlamp is operated and the shutter is momentarily opened, said vertical support and said guide member having a shielded portion that is provided for the purpose of a visual test with three openings at different levelstherein. but suillciently adjacent to each other to be all within the area of the full opening of the said supported shutter, and behind which three openings the dropped element passes and which three openings all receive light from the said flashlamp, in the testing operation.

6. A testing equipment for photographic flashlamp synchronizers of the electromagnetic shutter-release type including, in combination, a vertical support and guide member provided with means for supporting a shutter and shutter tripping means, a flashlamp supported in front of said shutter, said supported shutter being interposed between said support and guide member and the flashlamp, a droppable element slidable downwardly in said member, a switch mounted on said support and guide member in the path of sliding movement of said dropable element, said switch being in electrical circuit with said shutter tripping means and with said ilashlamp and with the source of potential, so that when said switch is closed by the downward movement of said sensitized droppable element the flashlamp is operated and the shutter is momentarily opened, said vertical support and said guide member having a shielded portion that is provided for the purpose of a visual test with three openings at different a visual test but are not used when making a recorded test, said dropable element when the testing equipment is used for a recorded test, being a loaded sensitized-material holder presenting such material for the test.

7. A testing equipment for photographic flashlamp synchronizers of the electromagnetic shutter-reiease type, including, in combination, a vertical support and guide member provided with means for supporting ashutter and shutter-tripping means, a flashlamp supported in front of said shutter, said supported shutter being interposed between said support and guide member and the flashlamp, a sensitized material holder slidable downwardly in 'said member,- a switch mounted on said'support and guide member, in

the path of sliding movement of said holder, said main being in electrical circuit with said shutter tripping means'and with said flashlamp and with a source of potential, so that when said switch is closed by the "downward movement of said sensitized'material holder the flashlamp is operated and the shutter is momentarily opened, the said vertical support and guide member having a shielded portion with a plurality of adjacent light-passages in the face thereof, the said sensitizedmaterlal holder, in dropping. passing behind at least two bf the said light-passage openings, the said shutter being so supported that'the center of the shutter is in line-of-vision register with one of said light-passage openings. another oi said openings being exposed at all times to the light from the flashlamp.

8. A testing equipment for photographic flash lamp synchronizers of the electromagnetic shutter-release type. including, in combination, a vertical support and guide member provided with means for supporting a shutter and shutter-tripping means, a flashiamp supported in front of said shutter, said supported shutter being interposed betwean said support and guide member and the flashlamp, a sensitized-material holder slidable downwardly in said member, a switch mounted on said support and guide member in the path of sliding movement of said holder, said switch being in electrical circuit with said shutter tripping means and with said flashlamp and with a source of potential, so that when said switch is closed by the downward movement of said sensitized material holder the flashlamp is operated and the shutter is momentarily opened, said vertical support and guide member having a shielded portion provided in the face thereof with a light passage, the shutter being so supported that the center of the shutter is in line-of-vision register with said light passage, said face of the vertical support and guide member also having two other light passages in substantially vertical alignment with said first mentioned light passage, all three of said light passages'being sufliciently in proximity to be within the area of the shutter opening when fully open, there being in the face of the vertical support and guide member still another light passage which is in horizontal alignment with the first mentioned light passage whereby visual testing may be effected.

9. A testing equipment in accordance with claim 8, but wherein to provide such source of illumination, said vertical support and guide member have means to support at its back face a lamp for the purpose of illuminating th light passages of said vertical support and guide member in making a visual test.

10. A testing equipment for photographic flashlamp synchronizers including, in combination, a support member having a shielding face that is upright when in operating position, a lens board receiver attached to such shielding face of said support member and itself adapted to have attached temporarily thereto a camera lens board and shutter for the testing operation, a tripper for the hutter, an electrical switch mounted upon said support member in a position to be operated by a dropped element, which, for recorded tests, is a loaded sensitized-material holder presenting such material for the test, and which element is dropped in th test from a point above said switch, means for positioning in suitable relation to said upright support member a synchronizer battery case with flashlamp and source of potential, circuit wiring means for connecting said battery case, fiashlamp, source of potential, and an actuatable movable element that is connected to the tripper of the shutter used in the testing operation, the said support member with its said shielding face having a construction to receive and then to permit to drop therein behind said shielding face such element when released, so as by such dropping to operate said electrical switch, thereby to complete the circuit to the flashlamp and to actuate said movable element connected to said shutter tripper, the construction being such that the dropped element operates the electrical switch, therebyto complete the circuit to the fiashlamp and to actuate the said movable element connected to the shutter tripper, the said support member being provided in the said shielding face thereof with a perforated area for admitting light from the fiashlamp and behind which perforated area the dropped element passes, said perforated area admitting light to the sensitized material and being shaped to admit such light in varying intensity at different parts thereof, said shielding face being also pro vided with an opening which is positioned in lineof-vision register with the center of the opening of the shutter, said opening and said perforated area being in horizontal alignment, and said perforated area being exposed at all times to the light from the flashlamp.

11. A testing equipment for photographic flashlamp synchronizers of the electromagnetic shutter-release type including, in combination, a vertical support and guide member provided with means for supporting a shutter and shutter tripping means, a source of illumination supported by said vertical support and guide member, a droppable element slidable downwardly in said vertical support and guide member, a switch mounted on said support and guide member in the path of sliding movement of said droppable element, said switch being in electrical circuit with said shutter tripping means and with a source of potential, so that when\said switch is closed by the downward movement of said droppable element, the shutter is momentarily opened, said vertical support and guide member having a shielded portion provided with at least two substantially vertically aligned openings back of the shutter and in alignment with the shutter opening of the shutterwhen fully opened, said dropable element having at least two openings in substantially vertical alignment and in vertical alignment with the said openings in the said vertical support and guide member, said openings in the dropped element being provided with different light transmitting characteristics.

12. A testing equipment for photographic flashlamp synchronizers of the electromagnetic shutter-release type including, in combination, a vertical support 'and guide member provided with means for supporting a shutter and shutter tripping means, a source of illumination supported by said vertical support and guide member, a dropable element slidable downwardly in said vertical support and guid member, a switch mounted on said support and guide member in the path of sliding movement of said dropable element, said switch being in electrical circuit with said shutter tripping means and with a source of potential, so that when said switch is closed by the downward movement of said droppable element, the shutter is momentarily opened, said vertical support and guide member having a shielded portion provided with at least two substantially vertically aligned openings back of the shutter and in alignment with the shutter opening of the shutter when fully opened, said dropable element having three openings in substantially vertical alignment and in vertical alignment with said openings in the vertical support and guide member, said three openings being contrastingly colored.

JOSEPH A. SPRAGUE.

CERTIFICATE OF CORRECTION.

Patent No. 2,555,896. July 15, 19th.

JOSEPH A. SPRAGUE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 9, first column, line 2, for the claim reference numeral "8" read -ll; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 26th day of September, A. D. 19bi Leslie Frazer (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,355,896. July 15;, 19mg.

JOSEPH A, SPRAGUE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 9, first column, line 2, for the claim reference numeral "8" read --11--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 26th day of September, A. D. 191m.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

